UPDATED: Friday, October 30, 2009 --- 6:10 p.m.

A man already convicted as a sex offender is arrested again and tonight police worry there could be more children he targeted they still don't know about.

Tonight Warren Henkelman, 42, sits behind bars at the Columbia County Jail and it is what he may have done before he got there that has police concerned and wondering how many children are suffering.

On Tuesday Department of Justice special agents and Portage Police Officers searched Henkelman's apartment on Henry Drive.

A special agent says a computer in the apartment was involved in offering to distribute child pornography.

Henkelman was arrested and booked on charges of possessing child pornography, sexual assault of a child under the age of 12, sexual assault contact with a child under 13, and physical abuse of a child intentionally causing bodily harm and exposing his genitals.

Police worry there could be more victims.

Lieutenant Mark Hahn says, "A lot of times when you are dealing with people who commit crimes against children sometimes the children have never come forward and told anyone because they are scared of the person. Sometimes children have given some things or told something to their parents that their parents never expanded upon. In this type of situation when you have crimes against children there is always a concern that you could have victims out there."

Anyone with information about Henkelman is urged to call the Portage Police Department at 742-2171.

The Department of Justice investigation continues but according to a criminal complaint Henkelman has already admitted to downloading child pornography.

According to the Wisconsin Department of corrections sex offender registry, Henkelman was convicted of third-degree rape in the state of Oregon in 1992.

_______________________________________________________

Press Release from the Attorney General's Office:

PORTAGE – On October 27, 2009, special agents from the Wisconsin Department of Justice’s Division of Criminal Investigation and law enforcement officers from the Portage Police Department executed a search warrant at 212 Henry Drive, Apartment #8 in Portage, WI, the residence of Warren J. Henkelman after a computer at Henkelman’s residence was identified by a DCI agent as being involved in offering to participate in the distribution of known child pornography.

As a result of the search warrant Henkelman was taken into custody and booked in the Columbia County Jail on tentative charges of Possession of Child Pornography. A subsequent investigation was conducted that resulted in additional charges of 1st Degree Sexual Assault of a Child Under Age 12, 1st Degree Child Sexual Assault – Contact With a Child Under Age 13, Physical Abuse of a Child – Intentionally Cause Bodily Harm, and Exposing Genitals or Pubic Area.

According to the criminal complaint, during an interview with a DCI agent and a detective from the Portage Police Department, Henkelman admitted to downloading child pornography.

The investigation is continuing and the Portage Police Department encourages anyone with additional information regarding these crimes to contact the Portage Police Department at (608) 742-2171.

A copy of the criminal complaint is available at:
http://www.doj.state.wi.us/news/files/Henkelman_CriminalComplaint.pdf.

NBC15's Chris Woodard will have more on this story on NBC15 News at 6:00 p.m.